Process for converting mixed waste plastic (MWP) into valuable petrochemicals

Abstract

A process for converting mixed waste plastic (MWP) into valuable petrochemicals including feeding MWP to a pyrolysis reactor, converting the MWP into a gaseous stream and a liquid stream, and further processing the gaseous stream into valuable petrochemicals.

The invention claimed is: 
     
       1. A process for converting mixed waste plastic (MWP) into petrochemicals, the process comprising the steps of feeding mixed waste plastic (MWP) to a pyrolysis reactor, converting said MWP into a gaseous stream and a liquid stream, and further processing said gaseous stream into petrochemicals, said process further comprising the steps of:
 i) separating said liquid stream from said pyrolysis reactor into a first liquid portion and a second liquid portion, wherein said first liquid portion comprises more aromatics than the second liquid portion, and feeding said second liquid portion, together with a hydrocracker feed, to a hydrocracking unit; 
 ii) converting said second liquid portion, together with said hydrocracker feed, through hydrocracking into at least one gaseous stream and a second liquid stream; and 
 iii) further processing said at least one gaseous stream into the petrochemicals, 
 wherein said hydrocracker feed comprises crude distillation bottoms from at least one member selected from the group consisting of atmospheric distillation and vacuum distillation. 
 
     
     
       2. The process according to  claim 1 , further comprising no hydrogenation of any liquid stream coming from said pyrolysis reactor to free it from chlorine, before carrying out step i). 
     
     
       3. The process according to  claim 1 , further comprising feeding said mixed waste plastic (MWP) to a separator for PVC removal before feeding the MWP to said pyrolysis reactor to obtain a segregated PVC stream, wherein the segregated PVC stream is thermally dehydrochlorinated at a temperature of up to 450° C. and fed to said pyrolysis reactor. 
     
     
       4. The process according to  claim 1 , further comprising mixing said second liquid portion and said hydrocracker feed in such a proportion by weight or volume which results in the combined mixture prior to entering the hydrocracking unit or feed heaters having an S value measured as per ASTMD7157-12 of greater than 1. 
     
     
       5. The process according to  claim 1 , further comprising combining said gaseous stream originating from said pyrolysis reactor with said at least one gaseous stream originating from said hydrocracking unit and further processing the combined gaseous stream into petrochemicals. 
     
     
       6. The process according to  claim 1 , wherein a pyrolysis reaction is carried out in said pyrolysis reactor such that 90% of said liquid stream coming from said pyrolysis reactor boils below 350° C. 
     
     
       7. The process according to  claim 1 , wherein said gaseous stream from said pyrolysis reactor and said at least one gaseous stream originating from said hydrocracking unit are further processed in at least one processing unit selected from the group consisting of a steam cracking unit, a propane dehydrogenation unit, a butane dehydrogenation unit and a combined propane/butane dehydrogenation unit. 
     
     
       8. The process according to  claim 7 , wherein said gaseous stream from said pyrolysis reactor and said at least one gaseous stream originating from said hydrocracking unit are further processed in a steam cracking unit and at least one combined propane/butane dehydrogenation unit. 
     
     
       9. The process according to  claim 7 , further comprising separating said gaseous stream from said pyrolysis reactor and/or said at least one gaseous stream originating from said hydrocracking unit into a fraction comprising methane and hydrogen, a C2 fraction, a C3 fraction and a C4 fraction before further processing. 
     
     
       10. The process according to  claim 9 , further comprising feeding said C2 fraction to said steam cracking unit, said C3 fraction to said propane dehydrogenation unit and said C4 fraction to said butane dehydrogenation unit, respectively.